Impact Strength of Low-Carbon Steel 09G2S Welded Joint Metal

Comparative results are provided for Charpy V-notch impact bending tests of base metal and 09G2S steel welded joint metal before and after prolonged heat treatment (1200°C, 3.7 h exposure) with plotting of ductile–brittle transition curves and analysis of fracture surfaces after testing. Welded joints of 09G2S steel sheets with each other are prepared by automatic argon-arc welding with a consumable electrode in accordance with PNAE G-7-009-89. It is shown that in the temperature range from 200°С to room temperature impact strength of weld metal in the as-supplied condition is 2–2.5 times lower, and the beginning of ductile–brittle transition temperature is 90°С higher than for base metal. Long-term heat treatment expands the range of base metal ductile–brittle transition temperatures by 30°C and shifts the range of ductile–brittle transition temperatures in weld metal by at least 20°C towards higher temperatures.